Muscle Dysfunction Associated With ACL Injury and Reconstruction by Abbey C. Thomas A ...

235 Pages·2010·3.81 MB·English

Muscle Dysfunction Associated With ACL Injury and Reconstruction

by

Abbey C. Thomas

A dissertation submitted in partial fulfillment
of the requirements for the degree of
Doctor of Philosophy
(Kinesiology)
in The University of Michigan
2010

Doctoral Committee:
Associate Professor Riann M. Smith, Chair
Professor Edward M. Wojtys
Professor Ronald F. Zernicke
Assistant Professor Scott G. McLean
DEDICATION PAGE

To Kristin, for inspiring this research.

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ACKNOWLEDGEMENTS

I would like to extend a very heartfelt thank you to my advisor, Dr. Riann Palmieri-
Smith. The words on this page cannot do justice to the amount of respect and gratitude I
have for you and for everything that you have done for me. I will be forever indebted to
you for taking a chance on me and for providing me with a solid foundation upon which I
can succeed in the future. I appreciate your honesty, encouragement, and endless faith in
me. Thank you for being not only my advisor, but, when I needed it, my ―mom‖ and my
friend. You have been a far better mentor than I could have asked for and your passion
for research and dedication to your students has inspired me in more ways than you will
ever know. Thank you, Riann, for everything. I would not want to have gone through this
process with anyone else as an advisor.
I would like to thank the members of my dissertation committee. I have a tremendous
amount of respect for each of you. Thank you all for your collective knowledge and
experience that went in to making this possible. To Drs. Ed Wojtys and Ron Zernicke,
thank you for imparting on me some of the wisdom gained from your years spent in
research. I have truly learned a great deal from both of you. To Dr. Scott McLean, thank
you for being a part of this entire process. Thank you for never letting me settle, for
sharing with me the immense amount of knowledge that you have, and, most importantly,
for making me laugh through everything.
I would like to thank the orthopedic surgeons at MedSport for their willingness to let me
poach patients from their clinics. Also, thank you to those patients who agreed to
participate. None of this would have been possible without you sacrificing your time to
let me repeatedly shock you.
Thank you, also, to the members of the NRL, IBL, and BJIPRC. I would especially like
to thank the phenomenal undergraduate students who have worked with me throughout
my time here. You have been a bigger help than you can imagine. Thank you also to
Katie Antle and Mark Villwock for all of your assistance in recruiting participants for
these studies. Without the two of you, I would have no data. I would like to thank Priya
Venkatasubramanian. Thank you for saving me hours of frustration by writing all of my
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MatLab and Labview code. Without you, I would still be sitting in my office staring at a
blank m-file.
A sincere thank you goes out to three people without whom I would not be where I am
today. Dr. Jay Hertel was the first person ever to tell me that I was capable of obtaining
and succeeding with a PhD. Thanks, Jay, for setting this whole process in motion and for
supporting me throughout. Thank you also to Dr. Jen Medina-McKeon. You opened my
eyes to the world of knee OA and for that I am eternally grateful. You have been a
tremendous resource for me for many years now and I can only hope that continues well
into the future. Thank you to Dr. Pat McKeon for always having an encouraging word
and an invaluable life lesson to share. You gave me the courage to seek out a PhD
position at U of M and have been an endless source of inspiration ever since.
Thank you also to Pat VanVolkinburg and Brian Czajka for allowing me to teach within
the Athletic Training program throughout my time at U of M. This has been a
phenomenal opportunity from which I learned a great deal. I would also like to thank the
undergraduate athletic training students whom I have had the privilege of teaching these
past four years. Thank you for getting up and coming to class at 8 o‘clock on Friday
mornings. You all made my job worthwhile. I have learned a remarkable amount from
each of you and can only hope that you took something valuable away from my classes. I
will miss all of you.
I would also like to thank the friends who supported me through this process, the ones
whom I met at Michigan and the ones who have been with me from the beginning. Thank
you especially to Jess Deneweth for being an ever-positive, encouraging lab mate and
friend. No matter how rough things were, I knew I could always count on you for a smile.
You have no idea how much I will miss you. Thank you to my office mates, Sasha
Voloshina and Mélanie Beaulieu. You girls have made this past year enjoyable. I do not
know that there are two people in this world that could put up me as well as you did at
times. I will miss seeing you two every day.
Finally, and most importantly, I would like to thank my family. Thank you for supporting
and encouraging me, not only these past four years, but every day and in everything I do.
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Thank you for your understanding and patience every time I call home to apologize for
missing yet another family function because I have data to collect or a conference to
attend. Someday that will change. I never would have made it this far without your love
and support and cannot thank you enough for that. I love you!

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TABLE OF CONTENTS
DEDICATION PAGE .................................................................................................... ii
ACKNOWLEDGEMENTS ........................................................................................... iii
LIST OF FIGURES ...................................................................................................... vii
LIST OF TABLES ...................................................................................................... viii
LIST OF APPENDICES ................................................................................................ ix
ABSTRACT ....................................................................................................................x
CHAPTER 1....................................................................................................................1
INTRODUCTION ...........................................................................................................1
CHAPTER 2....................................................................................................................6
LOWER EXTREMITY MUSCLE STRENGTH FOLLOWING ACL INJURY AND
RECONSTRUCTION .....................................................................................................6
CHAPTER 3.................................................................................................................. 22
CONTRIBUTIONS OF CENTRAL ACTIVATION FAILURE AND ATROPHY TO
QUADRICEPS WEAKNESS ASSOCIATED WITH ACL RECONSTRUCTION ........ 22
CHAPTER 4.................................................................................................................. 35
NEUROMUSCULAR FATIGUE AND QUADRICEPS INHIBITION ALTER LOWER
EXTREMITY BIOMECHANICS ................................................................................. 35
CHAPTER 5.................................................................................................................. 51
DISCUSSION ............................................................................................................... 51
CHAPTER 6.................................................................................................................. 54
CONCLUSION ............................................................................................................. 54
CHAPTER 7.................................................................................................................. 57
RECOMMENDATIONS FOR FUTURE WORK .......................................................... 57
CHAPTER 8.................................................................................................................. 59
LITERATURE REVIEW .............................................................................................. 59
REFERENCES ............................................................................................................ 200

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LIST OF FIGURES
Figure 2.1. Hip flexion/extension strength testing position. ............................................ 10
Figure 2.2. Knee extension/flexion strength testing position. ......................................... 11
Figure 2.3. Ankle plantar flexion/dorsiflexion strength testing position. ......................... 11
Figure 2.4. Mean ± standard deviation hip, knee, and ankle muscle strength. ................. 13
Figure 3.1. Screenshot from strength and central activation failure testing (CAF). ......... 26
Figure 3.2. Scatter plot depicting the relation between quadriceps strength (Nm/kg) and
predicted strength from hierarchical regression. ............................................................. 28
Figure 3.3. Representative magnetic resonance image demonstrating quadriceps atrophy.
...................................................................................................................................... 29
Figure 4.1. Dynamic landing task.................................................................................. 40
Figure 4.2. Retro-reflective marker placement for dynamic landing trials. .................... 41
Figure 4.3. Pre- and post-fatigue joint rotations expressed as a percentage of the stance
phase. ............................................................................................................................ 44
Figure 4.4. Pre- and post-fatigue joint moments expressed as a percentage of the stance
phase. ............................................................................................................................ 45
Figure 4.5. Mean±standard deviation knee extension strength (Nm/kg). ........................ 46
Figure 4.6. Mean±standard deviation quadriceps central activation ratio. ....................... 47

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LIST OF TABLES
Table 2.1. Hip, knee, and ankle strength data (Nm/kg) for ACL-injured and control
subjects. Data are mean±standard deviation. .................................................................. 14
Table 2.2. Effect sizes and confidence intervals for strength data. ................................. 16
Table 3.1. Quadriceps maximal voluntary isometric contraction, cross sectional area, and
central activation ratio data for the injured and uninjured limbs. .................................... 29
Table 4.1. .Initial contact (IC) and peak stance (PS) knee joint rotations pre- and post-
fatigue. Data are mean±standard deviation. ................................................................... 43
Table 4.2. Knee joint moments (Nm/kg*m) pre- and post-fatigue. Data are
mean±standard deviation. .............................................................................................. 43
Table 4.3. Knee extension strength (Nm/kg) and quadriceps central activation ratio data.
Data are mean±standard deviation. ................................................................................ 43
Table 4.4. Effect sizes for time and group main effects. ................................................ 49

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LIST OF APPENDICES
APPENDIX A ............................................................................................................... 83
IRB CONSENT FORM ................................................................................................. 83
APPENDIX B ............................................................................................................... 99
DATA COLLECTION MATERIALS ........................................................................... 99
COLLECTION FORMS ......................................................................... 99
SUBJECT SELF-REPORT MEASURES ............................................. 102
REHABILITATON PROTOCOL ......................................................... 105
APPENDIX C ............................................................................................................. 114
SUPPLEMENTAL DATA .......................................................................................... 114
AIM 1 SUPPLEMENTAL DATA ........................................................ 114
AIM 1 SPSS OUTPUT ......................................................................... 125
AIM 2 SUPPLEMENTAL DATA ........................................................ 153
AIM 2 SPSS OUTPUT ......................................................................... 156
AIM 3 SUPPLEMENTAL DATA ........................................................ 167
AIM 3 SPSS OUTPUT ......................................................................... 180

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ABSTRACT

Muscle Dysfunction Associated With ACL Injury and Reconstruction
By
Abbey C. Thomas

Chair: Riann M. Smith

Anterior cruciate ligament (ACL) injuries occur in over 200,000 individuals per year in
the United States. Quadriceps central activation failure (CAF) is a common consequence
of these knee injuries, though why it presents remains elusive. Neuromuscular
impairments resulting from ACL injury may not be limited to the muscles crossing the
knee joint, however, though limited data are available to confirm this. The overall goal of
this dissertation is to examine the muscle dysfunction associated with ACL injury and
reconstruction, possible mechanisms leading to the lingering quadriceps muscle weakness
after ACL reconstruction (ACLr), and to determine the immediate impacts of this
weakness on the affected individual. In the first study, I sought to establish the presence
of muscle dysfunction throughout the lower extremity following ACL injury and ACLr. I
found that significant quadriceps and hamstrings strength deficits were present in the
injured/reconstructed limb compared to the contralateral side both pre- and post-
operatively, with pre-operative injured limb strength deficits also present compared to
healthy individuals. There was no hip or ankle weakness, however, compared to healthy
individuals. Given the presence of quadriceps weakness following ACLr, identifying the
contributing factors to this muscle weakness seemed critical. Therefore, in study two I
x